An interposer is a bridge connecting two or more electric devices with a fine pitch of electric contact pads to a substrate or board with a coarse pitch of electric contact pads. Through silicon via (TSV) is a vertical electrical connection completely through a silicon wafer or die. A silicon TSV interposer may connect multiple chips with fine pitch mounted on its top side to a substrate with a coarse pitch. A silicon TSV interposer may also connect chips mounted on its both sides. A silicon TSV interposer basically comprises a silicon substrate with TSVs and redistribution layers (RDL) and electric contact pads on its both sides. An organic TSV (though substrate via) interposer has the similar structure as a silicon TSV interposer, but use an organic substrate as base material. An organic TSV (though substrate via) interposer is much cheaper than a silicon TSV interposer. However, it is a big challenge to manufacture an organic TSV interposer with very fine features. For the application with fine features, a silicon TSV interposer is usually used. A silicon TSV interposer is usually manufactured by silicon wafer processing technology, while an organic TSV interposer may be manufactured by organic substrate or IC package assembly technologies. Recently, through glass via (TGV) glass interposers are being introduced and developed.
The methods of prior arts for making through silicon via (TSV), through organic substrate via (TSV) and through glass via (TSV) interposers are generally fall into two categories: one is substrate-based method (named herein), and the other is via-based method (named herein). The substrate-based method basically comprises: 1) opening a patterned array of vias on a substrate (a piece of silicon, organic substrate or glass), and 2) using a conductive material to fill in the patterned array of vias. And the via-based method basically comprises: 1) forming a patterned array of vias on a carrier, 2) using a substrate material to cover and seal the patterned array of vias. Through silicon via (TSV) interposers are based on the substrate-based method. And through organic substrate via (TSV) and through glass via (TGV) interposers may use both methods. Manufacturing interposers with through substrate vias is very time-consuming and expensive, especially for silicon interposers.
It is noticed in prior arts that the cross sectional structure of the traditional unidirectional fiber reinforced composites roughly has the similar structure as a TSV substrate. The unidirectional fiber reinforced composites are usually produced by using a matrix material to bond a bundle of unidirectional fiber together. It looks like a low cost method to produce TSV substrates by cutting a unidirectional metal wire reinforced composites into slices. However, a useful TSV substrate for packaging electronic devices cannot be simply produced in such a way. The basic reason is that through-substrate vias in a TSV substrate are precisely patterned, including 1) a feature of sawing streets (for dividing the vias into a plurality of via units for further cutting a TSV substrate into a plurality of TSV substrate units for packaging semiconductor chips and other electronic devices), 2) precisely defined via pitch from one to another, and 3) through-substrate vias may be depopulated wherein some vias are not formed in a regular via array. So, the traditional method using a matrix material to bond a bundle of fibers together cannot be directly used to produce a useful TSV substrate because the fibers are not precisely patterned. Furthermore, it is a challenge to integrate some other elements (such as capacitors, resistors or inductors) in an array of fibers and at desired locations. The present invention describes a method to overcome these issues so as to form a composite integrated with a precisely patterned array of metal wires wherein some other elements can also be added at desired locations. Such a composite is called an integrated ingot herein, which can be sawed into slices for further producing TSV substrates with other embedded elements at desired locations.